Atari Jaguar I guess. I loved Missile Command, Alien vs Predator, Syndicate, Tempest, and a couple of other titles but it really wasn't a wise investment.
PS3 would be worthless if it wasn't for the Blu Ray capability. I really only use it Yakuza titles.
I seriously regretted the X360 when I first bought it. I waited to pick one up until there was a good 10 titles I wanted on it. All the games turned out to be terrible aside from Dead Rising and VF and then it went RROD. Since then Alone in the Dark, Bayonetta, Deadly Premonition, KoF XIII, VF, and Lost Odyssey have made it a more worthwhile purchase. Without the Wii I'd probably be out of gaming entirely.